Needle bar lubrication



Dec. 28, 1954 K. NICOLAY NEEDLE BAR LUBRICATION Fifed July 12, 1951 Karl Nikolay United States Patent O NEEDLE BAR LUBRICATION Karl Nicolay, Bielefeld, Germany, assignor to Durkoppwerke Aktiengesellschaft, Bielefeld, Germany, a German company Application July 12, 1951, Serial No. 236,450

Claims priority, application Germany July 17, 1950 4 Claims. (Cl. 112-256) This invention concerns needle bar lubrication for sewing machines.

With sewing machines, especially high-speed industrial sewing machines, reliable lubrication of the needle bar and needle bar guide is of the greatest importance. Lubrication of the needle bar is usually insuflicient, which fact leads to trouble; or alternatively the lubrication is excessive in which case the oil easily penetrates between the needle bar and its guide. In the latter case the oil which has trickled through is then flung off and causes soiling of elevated work pieces.

The purpose of the present invention is to eliminate these faults and this is achieved by the fact that the needle bar together with its upper guide bearing constitutes a pump, and the pump action is controlled by suitable bores in the cross head of the needle bar and in the draw bar of the needle bar in such a manner that when the machine is running a sub-atmospheric pressure occurs in the interior of the needle bar, whereby oil emerging at the lower guide bearing of the needle bar, which oil collects in annular grooves at the lower end of the needle bar, is sucked back through cross-bores provided there into the interior of the needle bar and conveyed back into the casing.

The invention will be described further, by way of exarlrllplfi with reference to the accompanying drawings in w Fig. 1 is a section through the head of a sewing machine showing the needle bar guide and the needle bar lubrication constructed according to the invention;

Fig. 2 shows the needle bar with the bearing frame and the drive with the needle moving upwards; and

Fig. 3 shows the needle bar drive with the needle moving downwards.

As will be seen from Fig. l, the top edge 1 of the lower part of the bearing frame 1 for the needle bar 2 is recessed to present a sharp edge 1 and it thus acts as a scraping edge for oil which adheres to the needle bar. Small quantities of oil, which nevertheless still trickle through the bearing, collect in the annular grooves 3 in the needle bar 2 and pass from here through the bores 4 (Fig. 2) into the interior of the open-topped hollow needle bar 2, where they are sucked up by a wick 5. The top bearing member for the needle bar 2 of the bearing frame 1 has a length sufiicient to accommodate the reciprocatory motion of the needle bar 2 so that the open top of the needle bar 2 is always enclosed within the top bearing or guide member. The top bearing member is closed at the top for instance by means of a closure cap 7 and thus forms a cylinder in which the needle bar 2 works as a piston.

The hollow bored cross-head 8 of the needle bar, on which head the needle bar draw bar 9 acts, is in communication with the interior of the needle bar by way of a corresponding radial port in the needle bar 2. On upward movement of the needle bar by means of the crank and connecting rod shown in Figs. 2 and 3, the crossbores of the needle bar cross head 8 and of the needle bar draw bar or connecting rod 9 are in alignment, so that the air compressed in the upper bearing point of the needle bar can escape.

On the downward movement of the needle bar (Fig. 3), the cross-bores 10 of the needle bar cross head 8 and of the needle bar draw bar 9 are no longer in alignment so that owing to the sub-atmospheric pressure which arises in the top bearing region of the needle bar 2 there occurs a current of air in direction from the bores 4 of the needle bar 2 to the cross-head 8 of the needle bar, which current drags the oil with it into the wick 5. The cross-head and connecting rod act as a valve for the hollow interior of the needle bar.

On the subsequent return upward movement of the needle bar, the oil dragged along is then conveyed in the manner described above into the interior of the head 11 of the arm. The superfluous oil collecting in the head 11 of the arm is exhausted again through the pipe 12. The supply of oil to the running parts of the driving mechanism situated in the head 11 of the arm is effected through the hollow top shaft 13 along the path marked by the arrow.

According to the invention, it is now brought about, using very simple means, that oil can never pass by way of the needle bar or the needle onto the material being sewn, but that lubrication of the needle bar and needle bar guide is nevertheless guaranteed.

I claim:

1. In a sewing machine, a needle bar, upper and lower guides therefor, driving means for reciprocating said needle bar, said needle bar being open at the top and hollow from the top end to a point below the lower guide and having an external oil-collecting groove at such point with at least one port between that groove and the hollow interior of the bar, said upper guide having a length at least equal to the movement of said needle bar in its reciprocatory motion, said upper guide being closed at the top end and constituting a cylinder in which the open-topped end of the needle bar acts as a piston, at least one radial port in the needle bar, between the said guides, said driving means including a member having one end connected to said needle bar adjacent said radial port but oscillatably movable relative to said needle bar, said oscillatably movable end having a port movable into and out of communication with said radial port of said needle bar during the movement of said member relative to said needle bar, said ports being so arranged as to be in communication with each other as said needle bar rises and to be out of communication as said needle bar descends.

2. In a sewing machine, a needle bar, upper and lower guides therefor, said needle bar being open at the top and hollow from the top end to a point below the lower guide and having an external oil-collecting groove at such point with at least one port between that groove and the hollow interior of the bar, said upper guide being closed at the top end and constituting a cylinder in which the open-topped end of the needle bar acts as a piston, a cross-head extending laterally from the needle bar and having a radial port in it communicating with the hollow interior of the needle bar, a crank and connecting rod for reciprocating the needle bar, one end of the connecting rod fitting on the cross-head and having a radial port in it, said radial ports being so positioned as to be in register as the needle bar rises and out of register as the needle bar descends.

3. In a sewing machine, a needle bar, upper and lower guides therefona scraper lip on the top of the lower guide, said needle bar being open at the top and hollow from the top end to a point below the lower guide and having an external oil-collecting groove at such point with at least one port between that groove and the hollow interior of the bar, said upper guide being closed at the top end and constituting a cylinder in which the open-topped end of the needle bar acts as a piston, a

cross-head extending laterally from the needle bar and having a radial port in it communicating with the hol low interior of the needle bar, a wick within the hollow needle bar from the oil-collecting groove up to said radial port, a crank and connecting rod for reciprocating theneedle bar, one end of the connecting rod fitting on the cross-head and having a radial port in it, said radial ports being so positioned as to be in register as the needle bar rises and out of register as the needle bar descends.

4.-In a sewing machine, a reciprocating needle bar, upper and lower guides therefor, the upper guide being closed at the top by an attached cap and the lower guide having an oil-scraper lip at the top, a cross-head on the needle bar between said guides, a crank and connecting rod for reciprocating the needle bar, one end of the con- Iiecting rod fitting on said cross-head, said needle bar as the crank raises the needle bar and out of register being open at the top and hollow from its top end to a as the crank lowers the needle bar.

point below the lower guide and having a lateral port extencllling from its interior?1 into the saig cross-head, an r References Cited in the file of this patent oil-co ecting groove aroun the needle at at said point 0 below the lower guide and a port leading from said groove UNITED STATES PATENTS to the hollow interior of the needle bar, a wick in the Number Name Date needle bar from said groove up to the lateral port, and 1,097,403 Eichhorn May 19, 1914 radial ports in the cross-head and that end of the con- 1,686,439 Cooke Oct. 2, 1928 nesting rod fitting thereon, so placed as to be in register 10 2,056,644 Clayton Oct. 6, 1936 

